Needle bar oscillator adjusting means in sewing machines



W. ENGEL ETAL Feb. 17, 1959 NEEDLE BAR OSCILLATOR ADJUSTING MEANS IN SEWING MACHINES Filed Jan. 24, 1957 jm ema rs WOLFGANG IENGE ERNST United States Patent NEEDLE BAR OSCILLATOR ADJUSTING MEANS IN SEWING MACHINES Wolfgang Engel, Bielefeld', and Ernst Broedner, Hoberge uber Bielefeld, Germany, assignors to Phoenix-Naehmaschinen A. G., Baer & Rempel, Bielefeld, Germany The invention relates to sewing machines of the type adapted for zig-zag stitching and as particularly concerned with means for adjusting the position of the needle with respect to the material sewed on the machine.

Many zig-zag sewing machines are so constructed that the pivot axis of the needle bar oscillator is disposed horizontally and perpendicularly with respect to the longitudinal axis of the machine. In machines of this type the journalling of the needle bar oscillator has already been provided in such a manner that the needle bar oscillator is adjustable in the head of the machine in the direction of its pivot axis. As a result of this axial adjustability of the pivot axis in the head of the machine the operator is enabled to adjust the alignment of the needle with the needle hole in the stitch plate in the direction of material feeding. However, it is notpossible by means of the ad justability of the needle bar oscillator axially of its pivot axis to control-the lateral deflection of the needleperpendicularly with respect to the direction of material feeding. Ifor the purpose of producing the zig-zag' transverse stitc It is, therefore, an objectof the invention to provide a journalling arrangement and construction of'the drive for the needle bar oscillator in a manner which permits adjustment of the needle bar in the direction of material advancement, or feed, as well as also transversely of the direction of material feed.

In accordance with the invention this is accomplished in a manner thatrin a zig zagsewing machine of the aforementioned known type additional arrangements are made whereby an adjusting lever is provided upon the needle bar oscillator which'is coupled with the drive mechanism of the type known per se, and which can be fixedly set in any angular position desired with respect to the pivot axis of the needle bar oscillator.

If adjustment is required of the needle position relative to the needle hole transversely to material feed, it is sufficient to release the connection between the adjusting lever and the needle bar oscillator, to adjust the position of the needle with the needle bar with respect to the needle hole and then to tighten the connection between the adjusting lever and the needle bar oscillator, which connection'is preferably in the form-of a screw clamp. This adjustment should be arranged to be undertaken at the factory duringtest runs of the machines, but at any rate it facilitates the foolproof and orderly mounting of the oscillator with its needle b'ar. Due to the fact that the journalling of the needle bar oscillator in the machine is adjustable inthe axial direction of its -pivot'axis, it is possible to properly correct any error arising during the alignment of the needle with respect to theneedlehole.

The fact that the adjusting lever may be positioned upon the needle bar oscillator in any desired angular orientation has-further essential advantages. With such'an arrangement it is possible to adapt the device to the different types of needle bar'oscillat'or drives, regardless of whether the drive mechanism for the oscillator bar is disposed nice 2 above the drive shaft, at the approximate height of the drive shaft or below the drive shaft. Accordingly it is possible to adapt the same needle bar oscillator to the different types of sewing machines and to the drives of the oscillator bar.

This arrangement of the adjusting lever upon the needle bar oscillator permits furthermore that this adjusting lever can be made of a material which is specifically lighter than that of which the oscillator bar proper is made, or the arrangement of the particular adjusting lever makes it possible, when a specifically heavier material is used, to make the dimensions of this lever so small that in any event the adjusting lever proper'has a minimum effect on the swinging mass of the oscillator lever. It is especially desirable in rapidly rotating sewing machines that the swinging or moving masses are as small as possible with respect to the oscillator. Inasmuch as the flawless stitch formation of the sewing machine requires the smallest possible load or stress on the movable drive components, particularly to obtain smaller inertia forces of the swinging components, it has been found to be particularly advantageous to insure that the pivot axis of the needle bar oscillator in the head of the arm of the sewing machine is located below the lower dead center point of the stud of the crank of the arm shaft or, on the other hand, above the upper dead center point of the needle bar block. This arrangement provides on the one hand that the magnitude of the angle of rotation is kept within predetermined limits, which permit that the point of the gripper reliably seizes the loop of the upper thread which has been formed, while on the other hand the lateral deflection of the needle bar block is relatively small, so that advantageous conditions are provided for the transfer of forces from the stud of the arm' shaft crank to the needle bar block. This advantageous condition then makes it possible to construct a needle bar joint which is particularly simple.

If care is taken in the zig-zag sewing machine in accordance with the invention that the upper needle bar journal of the needle bar oscillator is located at: the level of the pivot axis of the oscillator, then the weight of the mass which is required for this needle bar journal is practically located at the level of the pivot axis, so that that part of the weight of the oscillator has little or no noticeable effect on-the occurring inertia forces.

To be sure, it is already known in zig-zag sewing machines having stationary stitch plates which operate as straight forward sewing ma'chinesto provide the bar for the stepper with a swinging movement transversely to the direction of the material feed. For this the pivot stud for the drive of the presser foot bar is eccentrically journalled in order to adjust the position of the lateral deflection of the presser foot bar in relationto the needle bar which is not laterally adjustable. Thus this machine is not provided with a needle bar oscillator. In accordance with the invention, however, the needle bar oscillator is arranged to be adjustable about its pivot axis in the direction of material'feed. Moreover, it is achieved by means of the adjusting lever which can be coupled to the drive mechanism of the oscillator that an adjusting possibility for the needle bar is provided transversely with respect to the material feed. Only these two adjustment possibilities obtain the flawless and simple mounting of the needle bar oscillator with respect to the position of the needle bar in the needle hole of the stitch plate, which is obtained in a manner that both adjustments can be undertaken independently of one another and without interference with one another. Such independent double adjustment of the needle bar oscillator would not be possible by means of an eccentric stud in lieu of the adjusting lever in accordance with the invention, of thetype'known' for the control of the presser bar of the sewing machine mentioned above.

The invention will be better understood from the following description with reference to the drawings showing embodiments of the invention and in which Fig. 1 illustrates the oscillator drive mechanism in a cross-section taken along line II of Fig. 2,

Fig. 2 is a front view of the machine with the cover removed showing the oscillator drive mechanism,

Fig. 3 is a section along line II of Fig. 2 in which the drive means for the needle bar oscillator is disposed below the arm shaft, and

Fig. 4 is a section along line II of Fig. 2 in which the drive means for the needle bar oscillator is disposed substantially at the level of the arm shaft.

The arm shaft 2 is journalled in the arm and carries at its forward end the pitman crank 3. The stud 4 of the pitman crank is fastened to the pitman and is engaged by the eye 5a of the needle bar joint 5 while the other eye 5b of this joint engages the stud 6 of the needle bar block 7. The block 7 is secured to the needle bar 8 by clamping and needle bar 8 is guided in the needle bar oscillator 9 in bearing portions 10 and 11. The needle bar block 7 is provided with a nose 12 which is disposed in the slot 13 of the needle bar oscillator 9 for straight line guidance. The needle bar oscillator 9, in turn, is journalled between pointed studs 14 provided in the head of arm 1 below the dead center position of the stud 4 of the pitman of the arm shaft and above the upper dead center position of the needle bar block 7 for the purpose of maintaining the lateral deflection of the needle bar joint 5 and at the same time the oscillating nose of the oscillator as small as possible. Conical bores 15 are provided on both sides of the needle bar oscillator 9 into which project the pointed studs 14. These pointed studs are axially adjustable in the head of the machine under control of set screws 14a. The conical bores 15 are at the upper end of the needle bar oscillator 9 at the level of the upper needle bar bearing 11. Thus the needle bar oscillator pivots or swings in a known manner about a horizontal axis which is disposed perpendicularly with respect to the longitudinal axis of the machine.

In order to further decrease the oscillating mass the adjusting lever 17 of the needle bar oscillator 9 is made especially light, either of casting material or of spring steel. This adjusting lever 17 engages the stud 16 formed on needle bar oscillator 9 in the manner of a clamp by means of clamp screws 17a, which stud is disposed concentrically with respect to the conical bore 15 of the oscillator 9 at the side remote from the operating side. Depending on the drive means used for the lateral deflections of the oscillator 9, the free end of the adjusting lever 17 may be below the pivot point 14b as illustrated by lever 17b in accordance with Fig. 3, or at the level of the pivot point 140 as shown in Fig. 4 by adjusting lever 170, or above the pivot point 14d as shown by adjusting lever 17 of Fig. 1. In all cases the adjustment of the needle laterally with respect to the needle hole is readily made by means of set screws 17a.

The pointed stud bearing makes it possible for the needle bar oscillator 9 in combination with the clamping levers 17 to 170 to align the needle in two planes with respect to the needle stitch hole 34 of the stitch plate 35. To make it possible to satisfactorily and automatically oil the sliding areas of oscillator bar 9 such as the pointed stud bores 15, upper and lower needle bar bearings 10 and 11, as well as the guide slot 13 of the needle bar block 12, the entire oscillator. bar is pressed of powdered metal and the pores of the oscillator bar are saturated in oil.

As mentioned above, it is possible to securely clamp the adjusting levers 17 to 170 upon the projection 16 of the needle bar oscillator 9 in any desired position. Consequently, it is possible in the dilferent types of machines 4 with different driving means for the lateral deflections of the needle bar 9, to use always the same needle bar oscillator.

Fig. 3 shows a machine where the drive means for the lateral deflections of the oscillator 9 is disposed below the arm shaft 2. It comprises a drive shaft 18 driven by the shaft 2 with a pair of worm gears 19 and 20 and upon which the cam 21 is secured, as well as guide 22 connected at its free end to the downwardly extending adjusting lever 17b.

Fig. 4 illustrates a machine where the drive means for the lateral deflections of the needle bar oscillator 9 is disposed substantially at the level of the arm shaft 2 and which is driven by a drive shaft 23 driven by way of gears 24, 25 from the arm shaft 2 and which extends horizontally. A cam 26 is secured to this drive shaft 23 which is connected by means of guide 27 to the lever 17c extending substantially horizontally.

Fig. 1 illustrates a machine having the drive mechanism for the lateral deflections of the needle bar oscillator 9 above the arm shaft 2. The driving of the shaft 28 is effected by arm shaft 2 by way of gears 29 and 30. A triangular cam 33 is secured to this shaft 28 which is engaged by the bifurcated lever 31 which is pivotally connected to the upwardly extending adjusting lever 17 at a joint 32. The adjustments for changing the stitch width and stitch location of the needle are effected in a known manner and are not illustrated.

To complete the drawings the thread feeder 36 with its connecting lever 37 journalled in the machine arm is illustrated in Fig. 2.

Having now described our invention with reference to the embodiments illustrated in the drawings, we do not wish to be limited thereto, but what we desire to protect by Letters Patent is set forth in the appended claims.

We claim:

1. In a zig-zag sewing machine including a housing and a drive shaft having a crank mounted in said housing, a needle bar operably connected to said crank on said drive shaft, a needle bar oscillator pivotally mounted in said housing and having a pivot axis extending in a plane disposed perpendicular to the longitudinal axis of the machine and drive mechanism for reciprocating said oscillator connected to said drive shaft, adjusting means for said needle bar oscillator comprising means for adjusting the needle bar oscillator in the direction of said pivot axis transversely of said housing and means including a lever secured at one end to said oscillator concentrically with respect to said pivot axis and adjacent thereto, and angularly adjustable relative to said pivot axis and connected at the other end to the said oscillator drive mechanism.

2. In a zig-zag sewing machine including a housing and a drive shaft having a crank mounted in said housing, a needle bar operably connected to said crank on said drive shaft, a needle bar oscillator pivotally mounted in said housing and having a pivot axis extending in a plane disposed perpendicular to the longitudinal axis of the machine and drive mechanism for reciprocating said oscillator connected to said drive shaft, adjusting means for said needle bar oscillator comprising means for adjusting the needle bar oscillator in the direction of said pivot axis transversely of said housing and means including a lever secured at one end to said oscillator concentrically with respect to said pivot axis and adjacent thereto, and angularly adjustable relative to said pivot axis and connected at the other end to the said oscillator drive mechanism, a drive connecting block intermediate said needle bar and said crank, said pivot axis being disposed below the'lower dead center point of said crank and above the upper dead center point of said needle bar drive connecting block.

3. In a zig-zag sewing machine including a housing and. a dr ve s a having a srank mounted in said housing,

a needle bar operably connected to said crank on said drive shaft, a needle bar oscillator pivotally mounted in said housing and having a pivot axis extending in a plane disposed perpendicular to the longitudinal axis of the machine and drive mechanism for reciprocating said oscillator connected to said drive shaft, adjusting means for said needle bar oscillator comprising means for adjusting the needle bar oscillator in the direction of said pivot axis transversely of said housing and means including a lever secured to one end to said oscillator concentrically with respect to said pivot axis and adjacent thereto, and angularly adjustable relative to said pivot axis and connected at the other end to the said oscillator drive mechanism, said needle bar oscillator having a bearing adapted to receive the upper portion of said needle bar and said bearing being disposed proximate said pivot axis of said needle bar oscillator.

4. In a zig-zig sewing machine including a housing and a drive shaft having a crank mounted in said housing, a needle bar operably connected to said crank on said drive shaft, a needle bar oscillator pivotally mounted in said housing and having a pivot axis extending in a plane disposed perpendicular to the longitudinal axis of the machine and drive mechanism for reciprocating said os cillator connected to said drive shaft, adjusting means for said needle bar oscillator comprising means for adjusting the needle bar oscillator in the direction of said pivot axis transversely of said housing and means including a lever secured at one end to said oscillator concentrically with respect to said pivot axis and adjacent thereto, and angularly adjustable relative to said pivot axis and connected at the other end to the said oscillator drive mechanism, a drive connecting block intermediate said needle bar and said crank, said pivot axis being disposed below the lower dead center point of said crank and above the upper dead center point of said needle bar drive connecting block, said needle bar oscillator having a bearing adapted to receive the upper portion of said needle bar and said bearing being disposed proximate said pivot axis of said needle bar oscillator.

References Cited in the file of this patent Parry Dec. 15, 1953 

